[Mesa-dev] [PATCH] i965: Mask the cut index based on the index buffer type in 3DSTATE_VF.

[Kenneth Graunke]

On 05/23/2013 03:46 PM, Kenneth Graunke wrote:
> According to the documentation: "The Cut Index is compared to the
> fetched (and possibly-sign-extended) vertex index, and if these values
> are equal, the current primitive topology is terminated.  Note that,
> for index buffers <32bpp, it is possible to set the Cut Index to a
> (large) value that will never match a sign-extended vertex index."
>
> This suggests that we should not set the value to 0xFFFFFFFF for
> unsigned byte or short index buffers, but rather 0xFF or 0xFFFF.
>
> Fixes sporadic failures in the ES 3 instanced_arrays_primitive_restart
> conformance test when run in combination with other tests.  No Piglit
> regressions.
>
> Cc: Ian Romanick <idr at freedesktop.org
> Cc: Paul Berry <stereotype441 at gmail.com>
> Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>

NAK on this patch.  It looks like 0x133700ff is not supposed to match 
0xff in GL_UNSIGNED_BYTE mode.  I think i've found a bunch more bugs. 
Going to write some tests and new patches...